U.S. patent number 7,923,746 [Application Number 12/126,935] was granted by the patent office on 2011-04-12 for light emitting diode package structure and method for fabricating the same.
This patent grant is currently assigned to Industrial Technology Research Institute. Invention is credited to Chen-Peng Hsu, Hung-Lieh Hu, Chao-Wei Li, Yao-Jun Tsai.
United States Patent |
7,923,746 |
Tsai , et al. |
April 12, 2011 |
Light emitting diode package structure and method for fabricating
the same
Abstract
The present invention discloses a light emitting diode (LED)
package structure, which includes a carrier, a first protrusion, a
LED chip, and an adhesion layer. The first protrusion is disposed
on the carrier and has a first opening to expose the carrier,
wherein the first protrusion is formed by a thermal conductive
material. The LED chip is disposed in the first opening on the
carrier, and a ratio between a width of the first opening and a
width of the LED chip is 1.about.1.5. The adhesion layer is
disposed between the LED chip and the carrier to bond the LED chip
to the carrier.
Inventors: |
Tsai; Yao-Jun (Taoyuan County,
TW), Hsu; Chen-Peng (Kaohsiung, TW), Li;
Chao-Wei (Taipei, TW), Hu; Hung-Lieh (Hsinchu,
TW) |
Assignee: |
Industrial Technology Research
Institute (Hsinchu, TW)
|
Family
ID: |
41062049 |
Appl.
No.: |
12/126,935 |
Filed: |
May 26, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20090230417 A1 |
Sep 17, 2009 |
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Foreign Application Priority Data
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Mar 12, 2008 [CN] |
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2008 1 0083769 |
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Current U.S.
Class: |
257/99;
257/E33.058 |
Current CPC
Class: |
H01L
33/486 (20130101); H01L 33/60 (20130101); H01L
2224/8592 (20130101); H01L 2224/73265 (20130101); H01L
33/641 (20130101); H01L 2224/48247 (20130101); H01L
2224/32245 (20130101); H01L 2924/3025 (20130101); H01L
2224/48091 (20130101); H01L 2924/181 (20130101); H01L
2224/49107 (20130101); H01L 2224/32257 (20130101); H01L
33/62 (20130101); H01L 2224/48091 (20130101); H01L
2924/00014 (20130101); H01L 2224/73265 (20130101); H01L
2224/32245 (20130101); H01L 2224/48247 (20130101); H01L
2924/00 (20130101); H01L 2924/3025 (20130101); H01L
2924/00 (20130101); H01L 2924/181 (20130101); H01L
2924/00012 (20130101) |
Current International
Class: |
H01L
33/48 (20100101) |
Field of
Search: |
;257/40,79-82,88,98-100,741,749,773,786,791,E33.059,E33.06,E33.058
;438/48,22,25-26,69 ;331/485-486,499,502-504,506,511-512 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1487605 |
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Apr 2004 |
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CN |
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200972865 |
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Nov 2007 |
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CN |
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1256745 |
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May 2008 |
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TW |
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Other References
"1st Office Action of China Counterpart Application" issued on May
21, 2010, p.1-p.6. cited by other.
|
Primary Examiner: Pert; Evan
Attorney, Agent or Firm: Jianq Chyun IP Office
Claims
What is claimed is:
1. A light emitting diode (LED) package structure, comprising: a
carrier; a first protrusion on the carrier and having a first
opening to expose the carrier, and the first protrusion comprising
a thermal conductive material; a LED chip disposed in the first
opening on the carrier, and a ratio between a width of the first
opening and a width of the LED chip being larger than 1 and smaller
than or equal to 1.5 such that a gap existing between a sidewall of
the LED chip and an inner sidewall of the first opening; and an
adhesion layer disposed between the LED chip and the carrier to
bond the LED chip to the carrier.
2. The LED package structure as claimed in claim 1, wherein the
first protrusion and the carrier are integrally formed.
3. The LED package structure as claimed in claim 1, wherein a
portion of the adhesion layer is disposed in the gap.
4. The LED package structure as claimed in claim 1, further
comprising a first optical material layer, and the first optical
material layer being disposed on the inner sidewall of the first
opening and the carrier exposed by the first opening.
5. The LED package structure as claimed in claim 4, wherein the
first optical material layer is a reflective layer or a light
absorption layer.
6. The LED package structure as claimed in claim 1, further
comprising a first fluorescent material layer disposed in the first
opening.
7. The LED package structure as claimed in claim 1, further
comprising a transparent material layer disposed in the first
opening.
8. The LED package structure as claimed in claim 1, further
comprising a second protrusion disposed on the first protrusion and
having a second opening, and the second opening being connected
with the first opening and having a width larger than a width of
the first opening.
9. The LED package structure as claimed in claim 8, wherein the
carrier, the first protrusion, and the second protrusion are
integrally formed.
10. The LED package structure as claimed in claim 8, further
comprising a second fluorescent material layer disposed in the
second opening.
11. The LED package structure as claimed in claim 8, further
comprising a second optical material layer disposed on an inner
sidewall of the second opening.
12. The LED package structure as claimed in claim 11, wherein the
second optical material layer is a reflective layer or a light
absorption layer.
13. A light emitting diode (LED) package structure, comprising: a
carrier; a first protrusion on the carrier and having a first
opening to expose the carrier, and the first protrusion comprising
a thermal conductive material; a LED chip disposed in the first
opening on the carrier, and a ratio between a width of the first
opening and a width of the LED chip being between 1 and 1.5; and an
adhesion layer disposed between the LED chip and the carrier to
bond the LED chip to the carrier.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority benefit of Chinese application
serial no. 200810083769.9, filed on Mar. 12, 2008. The entirety of
the above-mentioned patent application is hereby incorporated by
reference herein and made a part of this specification.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a light emitting diode package
structure, and particularly relates to a light emitting diode
package structure having high thermal conduction efficiency.
2. Description of Related Art
In recent years, luminescence efficiency of light emitting diodes
(LED) has been constantly improved. Consequently, fluorescent lamps
and incandescent bulbs are gradually replaced with LEDs in some
fields, such as scanning light source which requires high speed
response, back or front light source of a liquid crystal display
(LCD), automobile dashboard illumination, traffic signs, and
general illumination devices. Typical LEDs are usually
semiconductor devices which use III-V compounds, such as GaP, GaAs,
and so on. LEDs convert electrical energy into light. When an
electric current is applied to a semiconductor device with the
aforesaid compounds, energy is released in the form of light
through the combination of electron and electron hole. LEDs have
advantages, such as faster response (about 10.sup.-9 S), smaller
size, lower power consumption, less pollution, higher reliability,
and capability for mass production. Accordingly, LEDs are widely
applied in many fields.
FIG. 1 is a schematic cross-sectional view depicting a conventional
light emitting diode package structure. Referring to FIG. 1, a
conventional light emitting diode package structure 100 consists of
a LED chip 110, a carrier 120, a conductive lines 132, a conductive
line 134, and a molding compound 140. Herein, the LED chip 110 is
disposed on the carrier 120, and the conductive line 132 and the
conductive line 134 electrically connect the LED chip 110 with the
carrier 120 respectively. The molding compound 140 is disposed on
the carrier 120 and covers the conductive line 132 and the
conductive line 134. The LED chip 110 is applied voltage difference
through the conductive line 132 and the conductive line 134, and
thereby a light emitting layer 112 of the LED chip 110 emits light
and generates heat.
It is noted that the carrier 120 and the molding compound 140 of
the conventional light emitting diode package structure 100 have
poor thermal conduction efficiency. Consequently, heat generated by
the light emitting layer 112 of the LED chip 110 can not be
released effectively. When a high electric current is applied, the
LED chip 110 is easily damaged for being overheated. Hence, a
conventional method, which uses a thermal conductive material, such
as metal, to fabricate the carrier 120, is provided to improve the
thermal conduction efficiency of a bottom 114 of the light emitting
diode package structure 100. However, such a method does not
improve the thermal conduction efficiency of a sidewall 116 of the
LED chip 110.
SUMMARY OF THE INVENTION
The present invention provides a light emitting diode (LED) package
structure, which comprises a carrier, a first protrusion, a LED
chip, and an adhesion layer. Herein, the first protrusion is
disposed on the carrier and has a first opening to expose the
carrier, and the first protrusion is formed by a thermal conductive
material. The LED chip is disposed in the first opening on the
carrier, and a ratio between a width of the first opening and a
width of the LED chip is 1 approximately, such that an inner
sidewall of the first opening is attached to a sidewall of the LED
chip. The adhesion layer is disposed between the LED chip and the
carrier to bond the LED chip to the carrier.
The present invention provides a light emitting diode (LED) package
structure, which comprises a carrier, a first protrusion, a LED
chip, and an adhesion layer. Herein, the first protrusion is
disposed on the carrier and has a first opening to expose the
carrier, and the first protrusion is formed by a thermal conductive
material. The LED chip is disposed in the first opening on the
carrier, and a ratio between a width of the first opening and a
width of the LED chip is larger than 1 and smaller than or equal to
1.5 such that a gap exists between a sidewall of the LED chip and
an inner sidewall of the first opening. The adhesion layer is
disposed between the LED chip and the carrier to bond the LED chip
to the carrier.
The present invention provides a method for fabricating a light
emitting diode package structure described as follows. First, a
substrate having a first surface is provided. Then, an adhesion
layer and a LED chip are disposed on the first surface of the
substrate, wherein the adhesion layer is bonded between the LED
chip and the substrate, and the LED chip comprises a second surface
away from the substrate. Next, a first thermal-conductive material
layer is formed on the first surface, wherein the first
thermal-conductive material layer comprises a first opening to
expose the LED chip, and an inner sidewall of the first opening is
attached to a sidewall of the LED chip.
The present invention provides a method for fabricating a light
emitting diode package structure described as follows. A substrate
having a recess is provided. Then, an adhesion layer and a LED chip
are disposed on a bottom of the recess, and the adhesion layer is
bonded between the substrate and the LED chip. A ratio between a
width of the recess and a width of the LED chip is larger than 1
and smaller than or equal to 1.5, and therefore a gap exists
between a sidewall of the LED chip and an inner sidewall of the
recess.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the invention and, together with the description,
serve to explain the principles of the invention.
To make the above purposes, features, and advantages of the present
invention more comprehensible, preferable embodiments accompanied
by drawings are detailed as follows.
FIG. 1 is a schematic cross-sectional view depicting a conventional
light emitting diode package structure.
FIG. 2 is a schematic cross-sectional view depicting a light
emitting diode package structure according to an embodiment of the
present invention.
FIGS. 3.about.8 are schematic cross-sectional views depicting a
variety of the light emitting diode package structure in FIG.
2.
FIG. 9 is a schematic cross-sectional view depicting a light
emitting diode package structure according to an embodiment of the
present invention.
FIG. 10 is a schematic cross-sectional view depicting a light
emitting diode package structure according to another embodiment of
the present invention.
FIG. 11 is a schematic cross-sectional view depicting a light
emitting diode package structure according to yet another
embodiment of the present invention.
FIG. 12 is a schematic cross-sectional view depicting a variety of
the light emitting diode package structure in FIG. 11.
FIGS. 13A.about.13D are schematic cross-sectional views depicting a
process flow for fabricating a light emitting diode package
structure according to an embodiment of the present invention.
FIGS. 14A.about.14C are schematic cross-sectional views depicting a
process flow for fabricating a light emitting diode package
structure according to another embodiment of the present
invention.
FIGS. 15A.about.15C are schematic cross-sectional views depicting a
process flow for fabricating a light emitting diode package
structure according to an embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
FIG. 2 is a schematic cross-sectional view depicting a light
emitting diode package structure according to an embodiment of the
present invention. Referring to FIG. 2, in this embodiment, a light
emitting diode package structure 200 comprises a carrier 210, a
first protrusion 220, a LED chip 230, and an adhesion layer 240.
Herein, the first protrusion 220 is disposed on the carrier 210 and
has a first opening 222 to expose the carrier 210. The first
protrusion 220 may comprise a thermal-conductive material layer. In
addition, a material of the thermal-conductive material layer may
comprise gold, silver, copper, indium, titanium, zinc, aluminum,
lead, tin, nickel, platinum, chromium, or a combination of alloys
thereof. Certainly, in other embodiments, the first protrusion may
comprise a stack of a plurality of thermal-conductive material
layers. In addition, a material of the stack of thermal-conductive
material layers may comprise gold, silver, copper, indium,
titanium, zinc, aluminum, lead, tin, nickel, platinum, chromium, or
a combination of alloys thereof. Furthermore, the carrier 210 may
comprise a substrate 212, a first conductive structure 214, and a
second conductive structure 216. The first conductive structure 214
and the second conductive structure 216 respectively pass through
the substrate 212.
The LED chip 230 is disposed in the first opening 222 on the
carrier 210. A ratio between a width W2 of the first opening 222
and a width W1 of the LED chip 230 is 1, and therefore an inner
sidewall 222a of the first opening 222 is attached to a sidewall
232 of the LED chip 230. In this embodiment, the width W1 (the
widest portion) of the LED chip 230 and the width W2 of the first
opening 222 are referred in the same cross-section.
It is noted that the present invention is not intended to limit the
relative heights of the first protrusion 220 and the LED chip 230.
It is to say that a height H1 of the LED chip 230 may be larger
than, smaller than, or equal to a height H2 of the first protrusion
220. In addition, the first conductive structure 214 and the second
conductive structure 216 are electrically connected with the LED
chip 230 respectively. The adhesion layer 240 is bonded between the
LED chip 230 and the carrier 210 to bond the LED chip 230 to the
carrier 210. A material of the adhesion layer 240 is, for example,
silver paste, solder, glass, alloy, or other suitable thermal
conductive materials. Hence, the adhesion layer 240 helps to
improve the thermal conduction efficiency of the LED chip 230.
In view of the above, the light emitting diode package structure
200 in this embodiment comprises the first protrusion 220 formed by
a thermal conductive material, and the first protrusion 220 is
attached to the sidewall 232 of the LED chip 230. Moreover,
compared with a conventional carrier 120 (referring to FIG. 1), the
first protrusion 220 is closer to a light emitting layer (not
shown) of the LED chip 230. Consequently, the first protrusion 220
in this embodiment helps to increase the thermal conduction
efficiency of the sidewall 232 of the LED chip 230, and release the
heat generated by the light emitting layer of the LED chip 230.
Therefore, the first protrusion 220 in this embodiment helps the
light emitting diode package structure 200 to prevent reducing
light emitting efficiency or damaging the LED chip 230.
The heat generated by the LED chip within the light emitting diode
package structure in this embodiment is removed through the first
protrusion attached to the sidewall of the LED chip so as to
enhance the thermal conduction efficiency of the light emitting
diode package structure. Persons skilled in this art may make some
modifications without departing from the spirit and scope of the
present invention. In addition, a variety of the light emitting
diode package structure 200 is described as follows.
In the present invention, an insulating substrate, a leadframe, or
a carrier substrate may serve as a substrate 212 depending on
requirements. In this embodiment, the substrate 212 is the
insulating substrate. A material of the insulating substrate is,
for example, ceramic. However, this embodiment is not limited
thereto. The insulating substrate may also be formed by other
suitable insulating materials.
FIGS. 3.about.8 are schematic cross-sectional views depicting a
variety of the light emitting diode package structure in FIG. 2.
Referring to FIG. 3, in this embodiment, a light emitting diode
package structure 300 is similar to the light emitting diode
package structure 200, and the difference lies in that the light
emitting diode package structure 300 and the light emitting diode
package structure 200 comprise different carriers 210. The carrier
210 of the light emitting diode package structure 300 may comprise
the substrate 212, a first conductive structure 214, a second
conductive structure 216. The LED chip 230 is disposed on the
substrate 212, and the first conductive structure 214 and the
second conductive structure 216 are respectively disposed on the
substrate 212 on two sides of the LED chip 230.
In this embodiment, the substrate 212 is, for example, a
silicon-on-insulator (SOI). For instance, the substrate 212
comprises a first semiconductor layer S1, a second semiconductor
layer S2, an insulating strip I1, and an insulating layer I2
arranged between the first semiconductor layer S1 and the second
semiconductor layer S2. The insulating strip I1 is disposed in the
second semiconductor layer S2 to divide the second semiconductor
layer S2 into a first portion A and a second portion B. The first
portion A is electrically connected with the first conductive
structure 214, and the second portion B is electrically connected
with the second conductive structure 216. Herein, a material of the
first semiconductor layer S1 and the second semiconductor layer S2
is silicon, for example. A material of the insulating strip I1 and
the insulating layer I2 is, for example, silicon oxide (SiO.sub.2).
In addition, the first conductive structure 214 and the second
conductive structure 216 are electrically connected with the LED
chip 230 respectively through a first conductive line C1 and a
second conductive line C2. Referring to FIG. 4, in other
embodiments, the adhesion layer 240 may comprise a first conductive
bump B1 and a second conductive bump B2, and the first conductive
structure 214 and the second conductive structure 216 are
electrically connected with the LED chip 230 respectively through
the first conductive bump B1 and the second conductive bump B2.
Referring to FIG. 5, in this embodiment, a light emitting diode
package structure 400 is similar to the light emitting diode
package structure 200, and the difference lies in that the light
emitting diode package structure 400 and the light emitting diode
package structure 200 comprise different carriers 210. In this
embodiment, the substrate 212 of the carrier 210 comprises a recess
212a, and the LED chip 230 is disposed in the recess 212a on the
substrate 212. Moreover, the light emitting diode package structure
200 further comprises a fluorescent material layer 250 disposed in
the recess 212a to cover the LED chip 230.
Referring to FIG. 6, in this embodiment, a light emitting diode
package structure 500 is similar to the light emitting diode
package structure 400, and the difference lies in that the light
emitting diode package structure 500 and the light emitting diode
package structure 400 comprise different carriers 210. In this
embodiment, the carrier 210 further comprises a housing 218, and
the first conductive structure 214 and the second conductive
structure 216 respectively pass through the housing 218.
In this embodiment, the substrate 212 is formed by a conductive
material, and the housing 218 is formed by an insulating material.
The conductive material is, for example, copper, aluminum, or other
suitable conductive materials. The LED chip 230 is electrically
connected with the substrate 212 through the adhesion layer 240,
and the substrate 212 is electrically connected with the second
conductive structure 216 through the second conductive line C2. In
addition, the LED chip 230 is electrically connected with the first
conductive structure 214 through the first conductive line C1.
Furthermore, the light emitting diode package structure 500 may
comprise an optical lens 260 disposed on the recess 212a.
Referring to FIG. 7, in other embodiments, a carrier of a light
emitting diode package structure 600 is, for example, a first
leadframe 612 having a recess 612a. The LED chip 230 is disposed in
the recess 612a and electrically connected with the first leadframe
612. In addition, the light emitting diode package structure 600
further comprises a second leadframe 614, a conductive line C, a
molding compound 260, and a fluorescent material layer 250. Herein,
the LED chip 230 is electrically connected with the second
leadframe 614 through the conductive line C. The fluorescent
material layer 250 is disposed in the recess 612a to cover the LED
chip 230. Furthermore, the molding compound 260 covers the
conductive line C.
FIG. 8 is a schematic cross-sectional view depicting a light
emitting diode package structure according to another embodiment of
the present invention. Referring to FIG. 8, in other embodiments, a
light emitting diode package structure 700 may further comprise a
reflective layer R disposed on the first protrusion 220 depending
on requirements. The first protrusion 220 comprises the first
thermal-conductive material layer 224 and the second
thermal-conductive material layer 226 arranged between the first
thermal-conductive material layer 224 and the reflective layer R,
wherein the first thermal-conductive material layer 224 is disposed
on the carrier 210. The reflective layer R is adapted for
reflecting a light generated by the LED chip 230 so as to increase
light utilization. For instance, a material of the first
thermal-conductive material layer 224 is copper, a material of the
second thermal-conductive material layer 226 is nickel, and a
material of the reflective layer R is sliver. In addition, this
embodiment does not limit the number of the thermal-conductive
material layers contained in the first protrusion 220. Therefore,
the first protrusion 220 may comprise a thermal-conductive material
layer or a plurality of thermal-conductive material layers.
FIG. 9 is a schematic cross-sectional view depicting a light
emitting diode package structure according to an embodiment of the
present invention. Referring to FIG. 9, in this embodiment, a light
emitting diode package structure 800 comprises a carrier 810, a
first protrusion 820, a LED chip 830, and an adhesion layer 840.
The first protrusion 820 is disposed on the carrier 810 and has a
first opening 822 to expose the carrier 810. The first protrusion
820 is formed by a thermal conductive material. The LED chip 830 is
disposed in the first opening 822 on the carrier 810. Moreover, a
ratio between a width W2 of the first opening 822 and a width W1 of
the LED chip 830 is larger than 1 and smaller than or equal to 1.5.
Therefore, a gap A exists between a sidewall 832 of the LED chip
830 and an inner sidewall 822a of the first opening 822. The
adhesion layer 840 is arranged between the LED chip 830 and the
carrier 810 to bond the LED chip 830 to the carrier 810.
In this embodiment, the first protrusion 820 and the carrier 810
are, for example, formed in one piece. The first protrusion 820 and
the carrier 810 may be formed by the same material (e.g. a thermal
conductive material). Because the first protrusion 820 and the
carrier 810 are formed in one piece and formed by the same
material, heat generated by the LED chip 830 is rapidly transferred
to the carrier 810 through the first protrusion 820. Consequently,
the light emitting diode package structure 800 has better heat
dissipation.
Furthermore, in this embodiment, a portion of the adhesion layer
840 may be disposed in the gap A depending on requirements. Hence,
the adhesion layer 840 not only bonds the LED chip 830 to the
carrier 810 but also bonds the LED chip 830 to the first protrusion
820. As a consequence, the LED chip 830 and the first protrusion
820 are steadily bonded. In addition, the heat generated by the LED
chip 830 is transferred to the first protrusion 820 through the
adhesion layer 840.
Depending on requirements, the light emitting diode package
structure 800 may further comprise a first optical material layer
850 disposed on the inner wall 822a of the first opening 822 and on
the carrier 810 exposed by the first opening 822. The first optical
material layer 850 may be a reflective layer or a light absorption
layer. If the first optical material layer 850 is a reflective
layer, the reflective layer is adapted for reflecting a light,
which is emitted from the LED chip 830 to the inner wall 822a of
the first opening 822 and the carrier 810 exposed by the first
opening 822, so as to enhance light utilization. If the first
optical material layer 850 is a light absorption layer, the light
absorption layer is adapted for absorbing a light, which is emitted
from the LED chip 830 to the inner wall 822a of the first opening
822 and the carrier 810 exposed by the first opening 822, so as to
unify a direction of the light emitted by the light emitting diode
package structure 800. A variety of the light emitting diode
package structure 800 is described as follows.
FIG. 10 is a schematic cross-sectional view depicting a light
emitting diode package structure according to another embodiment of
the present invention. Referring to FIG. 10, a light emitting diode
package structure 900 may further comprise a first fluorescent
material layer 860 disposed in the first opening 822 depending on
requirements. Moreover, in other embodiments, the light emitting
diode package structure further comprises a transparent material
layer disposed in the first opening of the first protrusion.
FIG. 11 is a schematic cross-sectional view depicting a light
emitting diode package structure according to yet another
embodiment of the present invention. Referring to FIG. 11, a light
emitting diode package structure 1000 may further comprise a second
protrusion 870 disposed on the first protrusion 820. The second
protrusion 870 has a second opening 872, and the second opening 872
is connected with the first opening 822. A width W3 of the second
opening 872 is larger than a width W2 of the first opening 822. In
this embodiment, it is noted that the width W2 of the first opening
822 and the width W3 of the second opening 872 are referred in the
same cross-section.
In this embodiment, the carrier 810, the first protrusion 820, and
the second protrusion 870 may be formed in one piece and formed by
the same material. In addition, the light emitting diode package
structure 1000 may further comprise a second fluorescent material
layer 890 disposed in the second opening 872. The second
fluorescent material layer 890 has a uniform thickness, and
therefore the light emitting diode package structure 1000 emits a
light with uniform color.
In this embodiment, the light emitting diode package structure 1000
may further comprise a transparent material layer 880 disposed in
the first opening 822. Herein, the transparent material layer 880
is formed by a suitable transparent material, such as epoxy resin
or silicon resin. The light emitting diode package structure 1000
may further comprise a second optical material layer O disposed on
an inner wall 872a of the second opening 872. The second optical
material layer O may be a reflective layer or a light absorption
layer. If the second optical material layer O is a reflective
layer, the reflective layer is adapted for reflecting a light
emitted from the LED chip 830 to the inner wall 872a of the second
opening 872, so as to enhance light utilization. If the second
optical material layer O is a light absorption layer, the light
absorption layer is adapted for absorbing a light emitted from the
LED chip 830 to the inner wall 872a of the second opening 872, so
as to unify a direction of the light emitted by the light emitting
diode package structure 1000.
FIG. 12 is a schematic cross-sectional view depicting a variety of
the light emitting diode package structure in FIG. 11. Referring to
FIG. 12, a light emitting diode package structure 1100 in this
embodiment is similar to the light emitting diode package structure
1000 in FIG. 11. The difference lies in that the carrier 810 in
this embodiment comprises the substrate 812, the first conductive
structure 814, and the second conductive structure 816.
Furthermore, the first conductive structure 814 and the second
conductive structure 816 respectively pass through the substrate
812 and the first protrusion 820. In this embodiment, the substrate
812 and the first protrusion 820 are formed by an insulating
material. The LED chip 830 is electrically connected with the first
conductive structure 814 and the second conductive structure 816
respectively through the first conductive line C1 and the second
conductive line C2.
FIGS. 13A.about.13D are schematic cross-sectional views depicting a
process flow for fabricating a light emitting diode package
structure according to an embodiment of the present invention.
First, referring to FIG. 13A, a substrate 1310 having a first
surface 1312 is provided. In the meantime, a surface treatment
process may be performed on the first surface 1312 of the substrate
1310. The surface treatment process is, for example, adapted for
forming a first thermal-conductive material layer on the first
surface 1312 or increasing adhesion between the first
thermal-conductive material layer and the substrate 1310.
Then, referring to FIG. 13B, an adhesion layer 1320 and a LED chip
1330 are disposed on the first surface 1312 of the substrate 1310.
Herein, the adhesion layer 1320 is bonded between the LED chip 1330
and the substrate 1310, and the LED chip 1330 has a second surface
1332 away from the substrate 1310.
Thereafter, referring to FIG. 13C, a first thermal-conductive
material layer 1340 is formed on the first surface 1312. The first
thermal-conductive material layer 1340 has a first opening 1342 to
expose the LED chip 1330, and an inner sidewall 1342a of the first
opening 1342 is attached to a sidewall 1332 of the LED chip 1330.
In this embodiment, a method for forming the first
thermal-conductive material layer 1340 comprises electroless
plating, electroplating, electrophoresis, electrodeposition, or a
combination of the above. Moreover, in other embodiments not
illustrated here, a method for forming the first thermal-conductive
material layer further comprises disposing a bonding layer and a
thermal conductive element on the first surface of the substrate,
wherein the bonding layer is bonded between the substrate and the
thermal conductive element.
In this embodiment, referring to FIG. 13D, a second
thermal-conductive material layer 1350 is formed on the first
thermal-conductive material layer 1340 after the first
thermal-conductive material layer 1340 is formed. Furthermore, in
this embodiment, a reflective layer R may be formed on the second
thermal-conductive material layer 1350 after the second
thermal-conductive material layer 1350 is formed. Herein, a
material of the first thermal-conductive material layer 1340 is
copper, a material of the second thermal-conductive material layer
1350 is nickel, and a material of the reflective layer R is
sliver.
FIGS. 14A.about.14C are schematic cross-sectional views depicting a
process flow for fabricating a light emitting diode package
structure according to another embodiment of the present invention.
The fabricating process flow in this embodiment is similar to the
fabricating process flow illustrated in FIGS. 13A.about.13D.
Referring to FIG. 14A, the difference lies in that this embodiment
further comprises forming a shielding layer 1360 on the second
surface 1332 and on a portion of the sidewall 1334 of the LED chip
1330, before forming the first thermal-conductive material layer
and after disposing the adhesion layer 1320 and the LED chip 1330
on the first surface 1312 of the substrate 1310. Then, referring to
FIG. 14B, the first thermal-conductive material layer 1340 is
formed on the first surface 1312. Thereafter, referring to FIG.
14C, the shielding layer 1360 is removed. A recess 1344 is formed
in the first thermal-conductive material layer 1340 after removing
the shielding layer 1360 and a fluorescent material layer 1370 is
formed in the recess 1344.
FIGS. 15A.about.15C are schematic cross-sectional views depicting a
process flow for fabricating a light emitting diode package
structure according to an embodiment of the present invention.
First, referring to FIG. 15A, a substrate 1510 having a recess 1512
is provided. In this embodiment, an optical material layer 1520 may
also be formed on an inner wall 1512a of the recess 1512. The
optical material layer 1520 is, for example, a reflective layer, a
light absorption layer, or other suitable optical material
layers.
Then, referring to FIG. 15B, the adhesion layer 1530 and the LED
chip 1540 are disposed on a bottom 1512b of the recess 1512, and
the adhesion layer 1530 is bonded between the substrate 1510 and
the LED chip 1540. A ratio between a width W1 of the recess 1512
and a width W2 of the LED chip 1540 is larger than 1 and smaller
than or equal to 1.5 such that a gap A exists between a sidewall
1542 of the LED chip 1540 and the inner wall 1512a of the recess
1512. Further referring to FIG. 15C, in this embodiment, a
fluorescent material layer 1550 may be formed in the recess
1512.
To sum up, the light emitting diode package structure of the
present invention has at least the following advantages: 1. The
light emitting diode package structure of the present invention
comprises the first protrusion formed by a thermal conductive
material, and the first protrusion is attached to the sidewall of
the LED chip. Hence, the first protrusion of the present invention
is adapted for enhancing thermal conduction efficiency of the
sidewall of the LED chip. Consequently, the first protrusion helps
the light emitting diode package structure to prevent reducing
light emitting efficiency or damaging the LED chip. 2. Compared
with a conventional carrier, the first protrusion of the present
invention is closer to the light emitting layer of the LED chip.
Therefore, the first protrusion helps to rapidly remove the heat
generated by the light emitting layer of the LED chip. 3. The first
protrusion and the carrier of the present invention are formed in
one piece and formed by the same material. As a consequence, the
heat generated by the LED chip is rapidly transferred to the
carrier through the first protrusion, so as to achieve better heat
dissipation of the light emitting diode package structure. 4. The
adhesion layer of the present invention not only bonds the LED chip
to the carrier but also bonds the LED chip to the first protrusion.
Consequently, the LED chip and the first protrusion are steadily
bonded. In addition, the heat generated by the LED chip is
transferred to the first protrusion and the carrier through the
adhesion layer. 5. The second fluorescent material layer of the
present invention has a uniform thickness, and therefore a light
emitted by the light emitting diode package structure has uniform
color.
Although the present invention has been disclosed by the above
preferable embodiments, they are not intended to limit the present
invention. Persons skilled in this art may make some modifications
without departing from the spirit and scope of the present
invention. Therefore, the protection range of the present invention
falls in the appended claims.
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